Improved 11‐year solar signal in the Freie Universität Berlin Climate Middle Atmosphere Model (FUB‐CMAM)
Improved 11‐year solar signal in the Freie Universität Berlin Climate Middle Atmosphere Model (FUB‐CMAM)
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DOI：
10.1029/2003jd004012
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发表时间：
2004-03
影响因子：
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通讯作者：
K. Matthes;U. Langematz;L. Gray;K. Kodera;K. Labitzke
中科院分区：
文献类型：
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作者：
K. Matthes;U. Langematz;L. Gray;K. Kodera;K. Labitzke
到目前为止，大气环流模式研究还不能令人满意地捕捉到观测到的平流层11年太阳信号的大小和特征。本文给出了用Freie Universitat柏林气候中层大气模式进行的模式试验的结果，这些结果与观测结果相当一致。这些实验使用了真实的光谱太阳辐照度变化、二维辐射化学传输模型中的臭氧变化以及整个平流层中观察到的赤道风廓线的松弛。在北方冬季的极地夜间急流（PNJ）异常，显着较弱的行星波活动，和较弱的平均纬向环流在太阳极大值条件下的现实极地向下传播的模式中再现。观测到的太阳与准两年振荡（QBO）之间的相互作用被捕获，平流层变暖优先发生在QBO的西相。只有动力活跃季节的异常幅度有所改善，而夏季信号和低纬信号仍然太弱。结果强调了赤道风的重要作用，在实现一个更现实的太阳信号，产生一个更现实的风气候。此外，他们证实了最近的结果，赤道风在平流层上部，该地区占主导地位的半年振荡，是一个重要因素，在确定年际变化的PNJ。
So far, general circulation model studies have not been able to capture the magnitude and characteristics of the observed 11-year solar signal in the stratosphere satisfactorily. Here results from model experiments with the Freie Universitat Berlin Climate Middle Atmosphere Model are presented that are in considerable agreement with observations. The experiments used realistic spectral solar irradiance changes, ozone changes from a two-dimensional radiative-chemical-transport model, and a relaxation toward observed equatorial wind profiles throughout the stratosphere. During Northern Hemisphere winter a realistic poleward downward propagation of the polar night jet (PNJ) anomalies, significantly weaker planetary wave activity, and a weaker mean meridional circulation under solar maximum conditions are reproduced in the model. The observed interaction between the Sun and the Quasi-Biennial Oscillation (QBO) is captured and stratospheric warmings occur preferentially in the west phase of the QBO. Only the magnitude of the anomalies during the dynamically active season improves, whereas the summer signal and the signal at low latitudes are still too weak. The results emphasize the important role of equatorial winds in achieving a more realistic solar signal by producing a more realistic wind climatology. Furthermore, they confirm recent results that equatorial winds in the upper stratosphere, the region dominated by the Semiannual Oscillation, are an important factor in determining interannual variability of the PNJ.